KR960006706B1 - Via contact manufacturing method - Google Patents

Abstract

The method of forming a via contact includes the steps of forming an insulating layer(3,4,5) on a first conductive line(2), etching the predetermined portion of the insulating layer to form a via contact hole(6), forming a thin tungsten layer(11) on the insulating layer including the via contact hole through sputtering at a low temperature and forming a thin titanium nitride layer(12) thereon, blanket-etching the titanium nitride layer by a predetermined thickness to remove it placed on the bottom of the via contact hole to expose the tungsten layer, selectively depositing a CVD tungsten layer in the via contact hole to form a via plug(7), and forming a second conductive line(8) on the resulting structure.

Description

Via contact manufacturing method

1A to 1C are cross-sectional views showing a bar contact manufacturing step according to the prior art.

2A to 2C are cross-sectional views showing a via contact manufacturing step according to the present invention.

* Explanation of symbols for the main parts of the drawings

1: lower layer 2: first metal wiring

3: first insulating layer 4: ground 2 insulating layer

5: third insulating layer 6: via hole

7: Via plug 8: Second metal layer

11: sputtering tungsten film 12: titanium nitride film.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a highly integrated semiconductor device, and more particularly, to a method of manufacturing a via contact connecting a metal layer and a metal layer in a DRAM, SRAM, and logic process of 16 mega or more. It's about.

As the semiconductor devices are highly integrated, the aspect ratio of the via holes increases, and the depths of the via holes are different from each other. Therefore, when a metal layer is deposited in the via holes, contact failure occurs due to poor layer covering at the bottom of the via holes.

In order to improve such contact defects, via plugs were formed in the via holes, and then metal layers were formed.

A process for manufacturing a via contact using a via plug according to the prior art will be described with reference to FIGS. 1A to 1C.

FIG. 1A shows a first metal wiring 2, for example, an aluminum metal wiring on the lower insulating layer 1, a thin first insulating layer 3 along the entire surface, and a planarizing agent thereon. 2 is a cross-sectional view in which an SOG film or an IMO (Inter Metal Oxide) film is formed, for example, and a third insulating layer 5 is formed thereon.

FIG. 1B illustrates the wet etching of the second insulating layer 5 using the contact mask after the process of FIG. 1A, and the dry etching of the second and first insulating layers 4 and 3 to expose the first rapid wiring 2. It is sectional drawing which formed via hole 6.

FIG. 1C illustrates a method of selectively depositing a chemical vapor deposition (CVD) tungsten film on the first metal wire 2 exposed to the via hole 6 to form a via plug 7 in the via hole 6, and then a second metal layer ( It is sectional drawing which formed 8).

However, when the CVD tungsten film is deposited by via plug on the first metal wiring made of aluminum, WF6 and the first metal wiring, which are used as reactive gases of the CVD tungsten film, react with each other, such as AlF₃ at the interface between the first metal wiring and the via plug. Foreign matter is formed, which increases the via resistance. In addition, since the CVD tungsten film deposition process is a high temperature process of 300 to 500 ° C., foreign substances such as H ₂ O are released from the SOG film or IMO film used as the second insulating layer and exist at the interface between the first metal wiring and the via plug. Increase resistance.

Therefore, the present invention forms a via hole in order to eliminate the factor of increasing the via resistance as described above, and then sputtering tungsten is deposited thinly on the surface exposed to the via hole at low temperature, and again, a titanium nitride film (TiN) is formed only on the sidewall of the via hole. It is an object of the present invention to provide a method for manufacturing a via plug by depositing a selective CVD tungsten film after forming a).

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

2A through 2C are cross-sectional views illustrating a step of forming a via hole and then manufacturing a via plug and a via contact according to the present invention.

2A shows a first metal wiring 2 formed on the lower layer 1, and the first insulating layer 3, the second insulating layer 4, and the third insulating layer 5 are laminated by a known technique. Afterwards (see FIG. 1A), the third insulating layer 5, the second insulating layer 4, and the first insulating layer 3 of the predetermined contact portion are sequentially etched by wet and dry etching using a contact mask. A via hole 6 through which the first metal wiring 2 is exposed is formed by a known technique (see FIG. 1B), and a low temperature PVD (Physical Vapor Deposition) method is formed on the via hole 6 and the third insulating layer 15. As a result, the sputtering tungsten film 11 is deposited in a thin thickness, for example, about 1000 mm, and the titanium nitride film 12 is deposited in a thin thickness, for example, about 700 mm by the PVD method.

FIG. 2B is a cross-sectional view of the titanium nitride film 12 deposited on the bottom surface of the via hole 6 after the process of FIG. 2A, and the titanium nitride film 12 is hardly deposited on the bottom of the via hole 6. In the RIE (Reactive Ion Etcher) reactor by using the BC13 and C12 gas to etch the titanium silicide film 12 of about 400 Å thick and the sputtering tungsten film 11 of the bottom of the via hole 6 is exposed.

FIG. 2C shows a via plug (7) by depositing a CVD tungsten film on the sputtered tungsten film (1l) using WVF ₆ , SiH₄, H ₂ (or Ar) in a low pressure chemical vapor deposition (LPCVD) reactor on the via hole 6. ), And then the second metal layer 8 is deposited by, for example, about 8000 Å by aluminum PVD, and then a pattern is formed.

According to the present invention described above it is possible to solve the problem that foreign matters such as H ₂ O is generated in the insulating layer due to the high temperature process when forming the via plug.

In addition, the reactant used in forming the via plug, for example, WF ₆ and the first metal wiring react to prevent the formation of the AlF 3 film at the interface between the first metal interface and the via plug, thereby reducing the via resistance.

In addition, by forming a three-layer structure of a sputtered tungsten film / titanide nitride film / CVD tungsten film in the via hole, it is possible to improve the EM and SM characteristics in the via contact.

Claims (4)

A method of manufacturing a via contact, comprising: forming an insulating layer on an upper portion of a first conductive layer wiring, etching a predetermined portion of the insulating layer to form a via hole exposing the first conductive layer wiring; Forming a sputtered tungsten film at a thin thickness, forming a titanium nitride film at a thin thickness on top of the same, and etching a predetermined thickness of the titanium nitride film by an entire etching process to remove the titanium nitride film at the bottom of the via hole, thereby sputtering tungsten A method of manufacturing a via contact, comprising: exposing a film, and selectively depositing a CVD tungsten film in a via hole to form a via plug, and depositing a second metal layer over the entire structure. The method of claim 1, wherein the sputtering tungsten film is deposited to a thickness of about 1000 kW by a low temperature PVD method. The method of claim 1, wherein the titanium nitride film is deposited to a thickness of about 700 GPa by PVD. The method of claim 1, wherein the titanium nitride film is etched to about 400 Å in thickness to expose the sputtered tungsten film at the bottom of the via hole.